A professor of mathematics sent a fax to his wife.
"Dear Wife:
You must realize that you are 54 years old, and I have
certain needs which you are no longer able to satisfy.
I am otherwise happy with you as wife, and I sincerely
hope you will not be hurt or offended to learn that by the time you receive this letter,
I will be at the Grand Hotel with my 18-year-old teaching assistant.
I'll be home before midnight.-
Your Husband"
When he arrived at the hotel, there was a faxed letter waiting for him that read as follows:
"Dear Husband:
You, too, are 54 years old, and by the time you receive this letter,
I will be at the Breakwater Hotel with the 18-year-old pool boy.
Being the brilliant mathematician that you are,
you can easily appreciate the fact that 18 goes
into 54 a lot more times than 54 goes into 18.
Don't wait up."